In a large bowl, toss the shrimp with olive oil, chili powder, garlic powder, salt, and pepper. Let marinate for 15 minutes.
While the shrimp is marinating, prepare the mango salsa. In a medium bowl, combine diced mango, red onion, cilantro, lime juice, and jalapeño (if using). Mix well and set aside.
Heat a large skillet over medium-high heat. Add the marinated shrimp and cook for 2-3 minutes on each side, or until they are pink and opaque. Remove from heat.
To assemble the bowls, divide the cooked quinoa among four bowls. Top each with diced avocado and cooked shrimp. Spoon the mango salsa over the top.
Serve immediately and enjoy!